Recently in electronic devices, high-speed and large-capacity transmission has been promoted, and the number of connector pins per one substrate is increasing. As a measure against the increase in the number of pins in recent electronic devices, the pin connection configuration has been changed from a double-sided contact type to a single-sided contact type. With the change in the pin connection configuration, the number of pins can be ensured, however connection per pin becomes vulnerable to physical impact, and instantaneous interruption of electrical connection easily occurs at the connector pin.
Under such a situation, in electronic devices, hot swapping enabling maintenance or function addition to be performed without interrupting the service, has been desired. Here when a substrate unit is forcibly inserted at the time of replacement or addition, insertion impact may be transmitted beyond the substrate unit to a substrate unit in a peripheral slot, to cause instantaneous interruption at a connector pin in the substrate unit being in service. For example, in a shelf-type electronic device, in a case where a member for insertion and removal (known as an insertion and removal handle or a card lever) is provided on the substrate unit side, if an operator does not use this member at the time of inserting a substrate unit, and tries to forcibly insert it with momentum (hereinafter, such a forcible insertion method is referred to as “accelerated insertion”), bumping impact of the substrate unit is transmitted to a substrate unit in a peripheral slot via a backboard of the shelf, to cause instantaneous interruption at the connector pin.
A technique described below (Japanese Laid-open Patent Publication No. 05-291771) is proposed as a measure against accelerated insertion in electronic devices, aiming at impact relaxation at the time of housing and inserting a relatively large heavy electronic device. That is, a buffering member made of hard rubber is fixed on a guide plate of an apparatus casing, and in a process of pushing a disk unit case having a disk device contained therein into the casing, a movable pin fitted to the disk unit case is struck against the buffering member to dampen the impulse at the time of insertion.